Method for Embossing Air-Laid Webs Using Laser Engraved Heated Embossing Rolls

ABSTRACT

A method of making an embossed air-laid absorbent sheet product includes depositing a dry web of fibers on a foraminous support; compacting the fiber web; embossing the compacted web with a laser-engraved roll with a hard rubber embossing surface, the hard rubber embossing surface having a plurality of sinuate bosses radially projecting circumferentially around the laser-engraved roll to provide the fiber web with a functional emboss pattern including a plurality of continuous sinuate compressed regions extending in a machine direction of the fiber web, the laser-engraved roll being heated to or maintained at a temperature of from about 100° F. to about 300° F.; and bonding the fiber web.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/935,825, filed Sep. 8, 2004, which is a continuation of U.S.application Ser. No. 09/562,302, filed May 1, 2000, now U.S. Pat. No.6,893,525, which claims the benefit of U.S. Provisional Application Ser.No. 60/132,598, filed May 5, 1999. The priorities of the foregoingapplications are hereby claimed and the entirety of their disclosuresincorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to air-laid absorbent sheet andmore particularly in preferred embodiments to a method of embossingair-laid absorbent sheet utilizing laser engraved, hard rubber, heatedembossing rolls.

BACKGROUND ART

Air-laid absorbent sheet products are known in the art. U.S. Pat. No.4,437,917 to Tao et al. describes a method for increasing the caliperand bulk of air-laid dry fibrous webs. The method generally includesmeasuring the downstream caliper of the bond curing drier and adjustingdrier conditions on the basis of the caliper measurements.

U.S. Pat. No. 4,482,308 to Johnson teaches an apparatus for depositingdry fibers on a foraminous support including offset suction and airdeflecting means for imparting a horizontal velocity to the fibers inthe direction of the moving wire. The patent reports more uniformdistribution of fibers in the product.

U.S. Pat. No. 4,476,078 to Tao describes that air-laid products areconventionally embossed either before or after the binder is applied andcured; each method having its advantages and drawbacks. Pre-embossing isreported to reduce line speed, while post-embossing lacks good embossingdefinition (col. 1, line 58-col. 2, line 13).

U.S. Pat. No. 4,612,231 of Bouchette et al. describes a pattern for anair-laid fibrous web of enhanced absorbency. According to the '231patent, absorption rates are increased when at least about 40 percent ofthe imprinted area of the web is compressed (col. 2, lines 23-28).

Another method of increasing the absorbency of air-laid webs isdisclosed in U.S. Pat. No. 5,128,082 to Makoui. The '082 patentdescribes making an absorbent structure by dry laying a fibrous webhaving incorporated therein a superabsorbent material such aspoly(acrylic acid) or a salt thereof and applying a latex coating to atleast one surface of the web.

Embossing cellulosic absorbent sheet products to alter their mechanicalor tactile characteristics is likewise known. There is shown in U.S.Pat. No. 1,808,536 to Fisk a method and apparatus for embossing papertissue and towels using an embossing roll with a wave-like pattern. Thepattern on the roll has a relief height of 0.075 inches or more abovethe general surface of the roll (col. 2, lines 69-75). The method isreported to be particularly suitable for wet creped products prior tothe web contacting the drier rolls.

U.S. Pat. No. D186,259 to Howell shows a puffed textile fabric with awave-like design. So also U.S. Pat. No. 728,828 to Arkell shows abidirectional wave pattern imposed on a paper structure.

U.S. Pat. No. 3,672,950 to Murphy et al. is directed to adhesivelylaminated crepe products wherein the plies are bonded in superposedrelation by an adhesive disposed between the webs (col. 2, lines 15-25).The adhesive may be applied in a wave-like pattern in the machinedirection (FIGS. 1, 4), while the webs may be embossed with a greatnumber of pin-like embossments. The embossments extend from the body ofthe web for a predetermined distance as required to keep the two webssuitably spaced, the two webs being superposed with the protuberances ofeach web facing the other web (col. 4, lines 29-37; col. 6, line 74-col.7, line 1).

In U.S. Pat. No. 4,339,088 to Niedermeyer there is described anembossing method to avoid nesting in convolutedly wound rolls whereinthe repeat length is at least as great as the circumference of the roll.In Example 1, a sine wave pattern of embossment nodes is laid out in themachine direction (col. 4, lines 5-35).

U.S. Pat. No. 5,861,081 of Bredendick describes a single-ply paper towelwith a plurality of infundibulate bosses formed therethrough. The towelhas areas of light bosses and heavy boss perforations which form islandsof heavy boss perforations surrounded by intersecting bands of lightbosses (col. 3, lines 33-38).

Wave-like patterns have also been employed to control fluid distributionin absorbent structures. U.S. Pat. No. Re. 29,789 to Kolbach discloses adiaper with various embossed patterns. There is disclosed, for example,an embossed roll with circumferential wave bosses (46, FIG. 1) extendingthe cross direction of a production line. The diapers have compressedchannels 72 with a wavy line profile which functions to direct fluid inthe longitudinal direction (col. 7, lines 60-63; col. 8, lines 40-44).

U.S. Pat. No. 2,788,003 to Morin discloses a multi-layered diaperembossed with a wave-like pattern. The wave-like pattern is formed byembossing strips of the absorbent layer 17 against the facing sheet witha hot embossing tool. col. 3, lines 34-43. The embossed strips operateto convey fluid in the direction of the embossed lines. col. 4, lines29-51.

U.S. Pat. No. 5,759,473 to Minke et al. describes a process forproducing a silicone coated embossing roll for continuously embossingthe surface of the thermoplastic film. A laser beam is used to cut intothe smooth silicone rubber surface of the roll and pattern a designwhich replicates the negative of a leather grain. Embossed rollsdescribed in the '473 patent are made by applying a smooth, siliconerubber coating to a steel roll. col. 2, lines 40-45.

There is described in U.S. Pat. No. 5,529,563 to Veith et al. a methodof embossing between unmatched male and female embossing elementswherein one of the embossing rolls may be made of rubber. According tothe '563 patent the material of the male and female embossing elementsis preferably a deformable material such as rubber, plastic and thelike. See col. 3, lines 53 to col. 4, line 20 for a general descriptionof the process.

U.S. Pat. No. 5,269,983 to Schulz describes a method of embossinginvolving a mated pair of resilient and rigid embossing rolls. Accordingto the '983 patent a laser can be utilized to form recesses in aresilient roll such that the resilient roll receives protuberances of arigid male embossing roll when the rolls are placed in contact.

U.S. Pat. No. 4,634,484 to Wagner discloses a method of producing anembossing roll for the continuous embossing of the surface of athermoplastic film. Sheets having desired grain patterns are mounted ona roller with edges abutting. Onto the surface of the grain pattern asilicone synthetic resin is applied as a uniformly thick coating with acoating knife as the roller rotates. The resin is hardened into a matrixand then peeled off the grain pattern. The matrix is placed with thepattern outward on a roller whose diameter pretty much matches thediameter of the embossing roll to be produced. The surface of a tubularthermoplastic film is embossed by contact with a cylindrical matrixunder heat and pressure. The embossed surface of the thermoplastic filmis once again embossed under heat and pressure in the areas along theabutting edges of the natural grain pattern on the roller so that anendless positive impression without seams in the grain pattern isproduced. Another layer of silicone rubber is applied to the positiveimpression which layer is vulcanized into a matrix which is peeled offthe positive form and then adhered to the circumferential surface of theembossing roll with the negative side out. With this embossing roller anatural leather grain can be embossed on a thermoplastic film withoutthe appearance of discontinuities at the abutting edges.

U.S. Pat. No. 4,917,903 to Mente discloses an apparatus for producingdecorative seams on films. The method involves using a die coated with apaste-like silicone rubber composition hardened and used to emboss alayer of plastic. See col 4, lines 49-56.

U.S. Pat. No. 2,943,560 to Wrob et al. discloses an embossing apparatusincluding an embossing clip with a flexible metal member to which issecured a lining of fabric and a molded embossing member preferably madeof plastic, rubber or similar material. See Col. 3, lines 35-40.

U.S. Pat. No. 1,820,338 to Youngchild et al. discloses an embossing rollprovided with a plurality of layers of hard rubber separated by layersof heavy fabric. The various layers are removable to expose successivehard rubber layers. See Col. 2, lines 78-83.

U.S. Pat. No. 3,425,347 to Nard discloses a printing plate including arubber layer having an outer printing surface and an inner matingsurface formed by a pattern of space uniform projections which relievetension and provide concavity of the printing surface when a layer ismounted and adhesively secured to a curved backing roll.

U.S. Pat. No. 3,347,162 to Braznell et al. discloses rubber printingplates and a method of making them.

As can be seen from the foregoing rubber surfaces have been used forembossing, printing, and like processes. It is further noted, however,that patterned hard rubber rolls have not generally been applied toindustrial processes for producing air-laid absorbent sheet where highspeed, superior emboss definition, and wear considerations areparamount. In such applications steel rolls are generally still employeddespite their higher manufacturing costs.

It has been found in accordance with the present invention that heated,hard rubber embossing rolls may be used to provide high quality embossdefinition in air-laid webs. The inventive rolls and process of thecurrent invention provide for more economical embossed rolls forair-laid products and also reduces the amount of time necessary toproduce an embossed roll of a desired proprietary pattern.

SUMMARY OF THE INVENTION

There is provided in accordance with the present invention a method ofmaking an embossed air-laid absorbent sheet product. The inventiveprocess includes: a) depositing a dry web of fibers on a foraminoussupport; b) compacting the fiber web; c) embossing the compacted webwith a laser engraved roll with a hard rubber embossing surface providedwith an embossing pattern having a depth of from about 0.005 inch (5mils) to about 0.125 inch (125 mils), the hard rubber embossing surfacebeing biased toward a second embossing surface selected from the groupconsisting of the surface of a nip roll and a foraminous web supportengaging a support roll; and d) bonding the fiber web.

A particularly preferred process of making an embossed air-laidabsorbent sheet product in accordance with the invention includes thesequential steps of: a) depositing a dry web of fibers on a foraminoussupport; b) compacting the fiber web; c) embossing the compacted webwith a laser engraved roll with a hard rubber embossing surface providedwith an embossing pattern having a depth of from about 5 mils to about125 mils, the hard rubber embossing surface being biased toward a secondembossing surface selected from the group consisting of the surface of anip roll and a foraminous web support engaging a support embossing roll;and d) bonding the fiber web. The steps of bonding and embossing may bereversed in a sequential process when thermal bonding is employed.

In a further aspect of the invention there is provided an absorbentsheet material including an air-laid fiber web provided with afunctional emboss pattern comprising a plurality of continuous sinuatecompressed regions in the air-laid web. The embossed pattern isimprinted on the air-laid web by way of a laser engraved roll with ahard rubber embossing surface provided with an embossing pattern havinga depth of from about 5 mils to about 125 mils, the hard rubberembossing surface being biased to a second embossing surface selectedfrom the group consisting of the surface of a nip roll and a foraminousweb support engaging a support embossing roll.

BRIEF DESCRIPTION OF DRAWINGS

The invention is described in detail below with reference to the variousfigures in which:

FIG. 1 is a schematic diagram illustrating the manufacture of anair-laid absorbent sheet product;

FIG. 2 is a schematic view in perspective of a pair of embossing rollswhich may be utilized in the apparatus of FIG. 1; and

FIG. 3 illustrates roll to wire embossing of an air-laid absorbent sheetin accordance with the present invention.

DETAILED DESCRIPTION

The invention is described in detail below for purposes of illustrationand exemplification only. Various modifications will be readily apparentto those of skill in the art within the spirit and scope of the presentinvention which is set forth in the appended claims.

In general, the present invention is directed to a method of making anair-laid absorbent sheet embossed with a heated, hard rubber patternedroll. The process involves: a) depositing a dry web of fibers on aforaminous, that is, porous support; b) compacting the fiber web; c)embossing the compacted fiber web with a laser engraved roll with a hardrubber embossing surface provided with an embossing pattern having adepth of from about 5 mils to about 125 mils, the hard rubber embossingsurface being biased toward a second embossing surface selected from thegroup consisting of the surface of a nip roll and a foraminous websupport engaging a support embossing roll; and d) bonding the fiber web.

The step of bonding the fiber web includes, in some embodiments, boththe steps of applying a polymer emulsion binder to the web and curingthe binder. Typically, the binder is dried at a first temperature andthen thermally cured at a second higher temperature as will becomeapparent from the discussion which follows. Most preferably, the step ofapplying binder to the web is subsequent to the step of embossing thecompacted web. However, the step of applying binder to the web may, insome embodiments, be carried out prior to the step of embossing the web.The web may also be bonded using low melting point polymers, such aspoly(ethylene), in the fiber web either in powder or fiber form. Ingeneral, any polymeric component with a melting or softening point lessthan about 250° F. or so is preferred. Bicomponent fibers with a lowmelting point component are particularly convenient. Low melting pointpolymers may be used alone or in combination with polymer emulsionbinders as desired.

In cases where thermal bonding is used, a particularly preferred processmay include the sequential steps of: a) depositing a dry web of fiberson a foraminous support; b)compacting the fiber web; c)bonding the fiberweb; followed by d) embossing the compacted web with a laser-engravedroll with a hard rubber embossing surface provided with an embossingpattern having a depth of from about 5 mils to about 125 mils, the hardrubber embossing surface being biased toward a second embossing surfaceselected from the group consisting of the surface of a nip roll and aforaminous web support engaging a support embossing roll.

In particular applications of the process, the surface of the nip rollis selected from the group consisting of an unpatterned rubber surfacehaving a hardness which is less than the hardness of the hard rubbersurface of the laser engraved roll, a patterned rubber surface having ahardness which is less than the hardness of the hard rubber surface ofthe laser engraved roll, an unpatterned steel roll, and a patternedsteel roll.

In general, the hard rubber, laser engraved surface, has a durometerhardness of from about 50 to about 100; with a durometer hardness offrom about 75 to about 100 being typical. Most preferably the hardrubber, laser engraved surface has a durometer hardness of from about 85to about 100.

The laser engraved embossing roll is typically heated to or maintainedat a temperature from about 100° F. to about 300° F. A temperature offrom about 200° to about 260° F. is more common especially withcellulosic fibers such as wood pulp fibers. The embossing rolls may beheated directly, for example, with steam, hot water, radiant heat or thelike or may be placed in proximity to a dryer or oven where the processheat will maintain the temperature of the roll. In some cases,frictional heat may provide the necessary energy to maintain the desiredtemperature.

While an embossed pattern depth of from about 5 to about 125 mils may beemployed, an embossing pattern on the roll with a depth of from about 10to about 75 mils is more typical; while a depth of from about 15 toabout 50 mils is preferred in some applications.

The laser engraved roll is suitably constructed having a steel roll coreprovided with a rubber sleeve with a thickness of from about 1/32 of aninch to about 1 inch in thickness. Most typically the thickness of therubber sleeve on the laser engraved roll is from about ¼ inch to about ¾inch. A thickness of about ½ of an inch is particularly preferred.

While the inventive method may be applied to a variety of air-laidabsorbent sheet products, most typically these products have a basisweight of from about 25 to about 400 pounds per 3000 square foot ream.Most preferably, the embossed air-laid absorbent sheet product of theinvention has a basis weight of from about 35 to about 150 pounds per3000 square foot ream and consists essentially of cellulosic fibers. Itis also possible to include synthetic fibers in the web. When syntheticfibers are employed, generally from about 5 to about 50% by weight ofsynthetic fiber based on the combined weight of synthetic fiber andcellulosic fiber is utilized. Most commonly, when synthetic fiber isemployed it is used in the amount of from about 7.5 to about 15% byweight based on the combined weight of synthetic fiber and cellulosicfiber. Synthetic fibers employed may be selected from the groupconsisting of rayon fibers, polyethylene fibers, polypropylene fibers,polyethylene terephthalate fibers, nylon fibers and mixtures thereof.Polyethylene and polypropylene fibers are particularly preferred in someapplications.

If additional bonding is desired, synthetic fibers with a relatively lowmelting point, or bicomponent fibers with a low melting point polymericcomponent may be included. Poly(ethylene) fibers or bicomponent fiberswith a poly(ethylene) component are particularly useful.

It is also possible to include a superabsorbent polymer component in theair-laid sheet of the present invention since the sheet is typicallyused as part of an absorbent product. The superabsorbent polymer isusually employed in the form of powder, granules or fibers depositedduring the process of initially forming the web on a foraminous support.However, a superabsorbent component may also be added during the step ofapplying binder to the web as should be apparent from the discussionwhich follows.

In a further aspect of the invention, there is provided an absorbentsheet material including an air-laid fiber web provided with afunctional embossed pattern comprising a plurality of continuous sinuatecompressed regions in the air-laid web. The embossed pattern isimprinted on the web by way of a laser engraved roll with a hard rubberembossing surface provided with an embossing pattern having a depth offrom about 5 mils to about 125 mils, the hard rubber embossing surfacebeing biased toward a second embossing surface selected from the groupconsisting of the surface of a nip roll and a foraminous web supportengaging a support embossing roll. The functional embossed pattern ispreferably generally sinosoidal and is applied in the machine directionof an air-laid web by an embossing roll with a plurality of continuousradially projecting bosses extending about the circumference of theembossing roll. In general, the plurality of continuous sinuatecompressed regions have a width of from about 0.007 inches to about0.060 inches. More preferably, the sinuate compressed regions have awidth of from about 0.015 inches to about 0.035 inches with a width ofabout 0.025 inches being particularly preferred. Absorbent materialprovided with a plurality of sinuate compressed embossed regions usuallyhas the embossed regions spaced at a distance from one another of fromabout 0.1 inches to about 1.0 inches. More typically, the regions arespaced from one another at a distance of from about 0.2 to about 0.5inches. A spacing between sinuate lines of about 0.3 inches isparticularly preferred in one embodiment. The embossed pattern on thesheet, whether sinuate or otherwise, is prepared by employing acorresponding boss on the laser engraved roll having a relief height offrom about 0.005 to about 0.125 inch (5-125 mils). A boss height of fromabout 0.015 inches to about 0.075 inches is preferred whereas a bossheight range from about 0.025 inches to about 0.050 inches isparticularly preferred.

When a sinuate pattern as further shown and described herein is employedthe sinuate compressed regions typically have a wave amplitude of fromabout 1 mil to about 8 millimeters. An amplitude of from about 2millimeters to about 5 millimeters is preferred; whereas a waveamplitude of about 3.5 millimeters is especially preferred in someembodiments. Also, when a sinuate pattern is used, the compressedregions in the sheet have a repeat frequency from about 0.5 to about 4wave crests per inch. A repeat frequency of the wave crest of from about1 to about 3 crests per inch is typically preferred; with a repeatfrequency of about 2 crests per inch being particularly preferred insome applications. These and other features will be further appreciatedby considering the following description and drawings provided herewith.

A continuous air-laid web in accordance with the present invention ismanufactured on a high speed manufacturing line as are well known in theart. There is shown schematically in FIG. 1 a continuous manufacturingline, known as an air-laid machine available from M&J or Dan Web Formingof Denmark. Web processing is typically pneumatically assisted in thistype of apparatus as is likewise well known in the art. Generally,processes for producing and embossing air-laid webs appear in U.S. Pat.Nos. 4,437,917; 4,482,308; 4,476,078; 4,612,231; 5,128,082, thedisclosures of which are incorporated herein by reference.

Apparatus 10 of FIG. 1 includes a plurality of conveyor wires orfabrics, conveyor wires 12, 14, 16, 18, 20, 22, 24 and 26 which areforaminous (that is porous) supports for the product as it ismanufactured in the various steps. The foraminous supports may be metalscreens or porous fabric as so desired. Wire 12, the forming wire, islocated underneath a pair of fiber distributors 28, 30 which deposit afibrous web onto forming wire 12 typically under suction provided to theunder side of the wire. The web is then conveyed to a pair of compactingrolls 32, 34 which are smooth surfaced and only slightly loaded in orderto compact the web and provide it with some modicum of strength. If sodesired, a pair of embossing rolls (not shown) could be disposed asindicated at A if it were desired to emboss the web at this point in theprocess. At A it would be convenient to perform roll to wire embossing,that is, employ a pattern roll as a top roll and utilize a support rollunder the wire as is shown in FIG. 3. Embossing rolls are typicallyheavily loaded or biased towards each other and the pattern roll ispreferably heated or maintained at an elevated temperature as notedabove in order to impress a pattern on the fabric.

After compaction the web is transferred to a web transfer sectionindicated at 36 where the web is transferred upwardly onto wire 14 asindicated by arrow 38 and eventually downwardly to an emboss section 40.In section 40 it is convenient to employ roll to roll embossing as isgenerally illustrated in FIG. 2, before the web is transferred to athird conveyor wire 16. Wire 16 transports the web to a spray cabin 42where a binder, typically a latex binder, is sprayed onto the web.Thereafter, the web is transferred to a fourth conveyor wire, 18, andfed to a dryer, 44. Typically the first application of binder is about5-10 weight percent based on the weight of dry fiber and dry binder,that is, solids content of the binder. After drying it would beconvenient to emboss the continuous web with roll to roll embossing atlocation B, however, it has been found that embossing in accordance withthe present invention is generally more effective prior to theapplication of binder.

The web is transferred from wire 18 to wire 20 where the web is conveyedto wire 22 which transports the web to a spray cabin 48 where binder isapplied to the other side of the web which was adjacent to wire in spraycabin 42. During the second application of binder typically about 5-10percent binder is applied to the web based on the web of dry fiber anddry binder material. It should be noted that while fiber is referred toas “dry”, it will be understood by those who are skilled in the art thatfiber as supplied to the manufacturing process typically includes a fewpercent moisture.

When a polymeric emulsion binder is used, it is typical to applyanywhere from about 5 to about 35 weight percent of binder, based on theweight of dry binder and dry fiber. From about 10 to about 30 percentbinder is more typical, with about 15 to about 25 percent binder beingeven more typical.

Following the second application of binder the web is transferred towire 24 and fed to dryer 50. Thereafter, the web is transferred to wire26. At the transfer point C it is convenient to emboss the web with rollto roll or roll to wire embossing as is the case at A. Wire 26 conveysthe web to a cure oven 52 for curing and finishing of the web which maybe embossed at location D with either roll to roll or roll to wireembossing if so desired. The embossing process of the present inventionis most preferably carried out at location A or at emboss station 40prior to the application of binder. However, the sinuate pattern, or anyother pattern for that matter, could be also applied at location B, C,or D or even after initial manufacture. The embossed rolls are locatedwith their longitudinal axis perpendicular to the machine directiongenerally indicated by arrow 54 and may be located as rolls 56, 58 whichare depicted in FIG. 1 and in FIG. 2. It shall be appreciated inconnection with FIGS. 1 and 2 that the radially projecting sinuatebosses shown on roll 56 extend around the entire circumference of theroll and are aligned in the machine direction, or the direction of thetravel of the web as it is produced. In this regard, arrow 54 is only ageneral indication of the machine direction but it should be readilyapparent that the sinuate pattern extends continuously along thecontinuous web in the machine direction from the point of application ofthe emboss to the web as can also be seen in FIG. 3. The sinuate embosspattern illustrated on the roll is thus in the direction perpendicularto the longitudinal axis of the emboss roll shown in FIG. 2.

There is shown in FIG. 2 diagrammatically the emboss rolls 56, 58 ofFIG. 1. Patterned roll 56 is typically steel or maybe hard rubber whilesmooth emboss roll 58 maybe rubber or steel, soft or hard material. Roll56 is provided with plurality of raised bosses 60 having a typical width62 of 0.025 inches, a relief height 64 (which may also be referred to asdepth) of typically of from about 0.015 to about 0.050 inches above thesurface 66 of the roll between the sinuate bosses. The bosses areseparated by a distance 68 of about 0.3 inches, have a wave amplitude 70(peak to trough) of about 3.5 mils and a repeat frequency 72 of about 2crests per inch. In operation rolls 56, 58 are loaded against oneanother under pressure with only the fibrous web separating them atlocation 40. It should be appreciated that the bosses at 60 are radiallyprojecting and extend around the entire circumference of roll 56 toproduce continuous compressed sinuate regions in the sheet so formed ascan be seen in sheet 74 of FIG. 3. On FIG. 3 like numerals indicatesimilar parts as in FIG. 2. It should be noted that the dimensions ofthe bosses generally correspond to the dimensions on the sheet except inthe case of the depth of the emboss which may or not have the sameapproximate dimensions on the sheet and roll. Thus, the repeat frequency72, the line width 62, the wave amplitude 70, and the spacing of thelines 68 is approximately the same on sheet 74 as it is on roll 56 whilethe depth of the pattern on the sheet may depend upon both the height ofthe bosses and the basis weight of the web product. It is likewise to beappreciated that rolls 56 and 58 may be located at location A on FIG. 1.In such a case the compacted dry formed web 76 is fed between the rollsas shown in FIG. 3.

As noted above, the rolls are heavily loaded against one another androll 56 is preferably heated to, or maintained at, a temperature ofbetween 100° F. and 300° F. Passing between the rolls in what is termedroll to wire embossing wherein roll 58 engages the underside of the wire78 as a support roll is shown in FIG. 3. The embossed sheet 74 isprovided with the sinuate pattern of roll 56.

The particular pattern is conveniently provided to the emboss roll bylaser engraving as is known in the art. It has been found thatparticular hardnesses in combination with the basis weights and themanufacturing of air-lay are particularly suitable for laser engravedhard rubber rolls. Typically the hard rubber surface is provided to theroll in the form of a sleeve 80 extending continuously around the rollwhich is applied in the form of a sheet, the various thicknesses ofwhich are recited above, which is melt sealed at the seam. The roll isthen engraved with any pattern so desired having the depths indicatedherein. It should be noted that any suitable rubber having hardnessproperties suitable for engraving air-laid web may be employed, however,rubbers which give off noxious gases upon heating should be avoided.Typical rubbers which may be used include: nitrile rubbers, hypalon orsuitable natural rubbers. Nitrile rubbers are particularly preferred insome applications.

The invention has been described in detail in numerous aspects andembodiments, further description being deemed unnecessary. Variousmodifications of specific embodiments within the spirit and scope of thepresent invention will be readily apparent to those who are skilled inthe art. Such modifications are within the spirit and scope of thepresent invention as set forth in the appended claims.

1. A method of making an embossed air-laid absorbent sheet productcomprising: depositing a dry web of fibers on a foraminous support;compacting the fiber web; embossing the compacted web with alaser-engraved roll with a hard rubber embossing surface, the hardrubber embossing surface having a plurality of sinuate bosses radiallyprojecting circumferentially around the laser-engraved roll to providethe fiber web with a functional emboss pattern including a plurality ofcontinuous sinuate compressed regions extending in a machine directionof the fiber web, the laser-engraved roll being heated to or maintainedat a temperature of from about 100° F. to about 300° F.; and bonding thefiber web.
 2. The method according to claim 1, wherein the hard rubbersurface has a durometer hardness of from about 50 to about
 100. 3. Themethod according to claim 2, wherein durometer hardness is from about 75to about
 100. 4. The method according to claim 3, wherein the durometerhardness is from about 85 to about
 100. 5. The method according to claim1, wherein the laser-engraved roll is heated to or maintained at atemperature of from about 200° F. to about 260° F.
 6. The methodaccording to claim 1, wherein the laser-engraved roll comprises a steelroll provided with a rubber sleeve of from about 1/32 inch to about 1inch in thickness.
 7. The method according to claim 1, wherein theplurality of continuous sinuate compressed regions have a width of fromabout 0.007 inches to about 0.060 inches.
 8. The method according toclaim 1, wherein the width is from about 0.015 inches to about 0.035inches.
 9. The method according to claim 1, wherein the plurality ofsinuate compressed region are spaced at a distance from one another offrom about 0.1 inches to about 1.0 inches.
 10. The method according toclaim 1, wherein the distance from one another is from about 0.2 inchesto about 0.5 inches.
 11. The method according to claim 1, wherein theplurality of continuous sinuate bosses have a height of from about 0.005inches to about 0.125 inch.
 12. The method according to claim 11,wherein the height is from about 0.010 inches to about 0.075 inches. 13.The method according to claim 12, wherein the height is from about 0.015inches to about 0.05 inches.
 14. The method according to claim 1,wherein the plurality of sinuate compressed regions have a waveamplitude of from about 1 millimeter to about 8 millimeters.
 15. Themethod according to claim 14, wherein the wave amplitude is from about 2millimeters to about 5 millimeters.
 16. The method according to claim15, wherein the plurality of sinuate compressed regions have a repeatfrequency of from about 0.5 to about 4 wave crests per inch.
 17. Themethod according to claim 16, wherein the repeat frequency is from about1 to about 3 wave crests per inch.
 18. The method according to claim 17,wherein the repeat frequency is about 2 wave crests per inch.